This chapter describes facilities for issuing and logging messages of
system administration interest. This chapter has nothing to do with
programs issuing messages to their own users or keeping private logs
(One would typically do that with the facilities described in
I/O on Streams).
Most systems have a facility called “Syslog” that allows programs to
submit messages of interest to system administrators and can be
configured to pass these messages on in various ways, such as printing
on the console, mailing to a particular person, or recording in a log
file for future reference.
A program uses the facilities in this chapter to submit such messages.